TraceMethodVisitor


1   /***
2    * ASM: a very small and fast Java bytecode manipulation framework
3    * Copyright (c) 2000-2005 INRIA, France Telecom
4    * All rights reserved.
5    *
6    * Redistribution and use in source and binary forms, with or without
7    * modification, are permitted provided that the following conditions
8    * are met:
9    * 1. Redistributions of source code must retain the above copyright
10   *    notice, this list of conditions and the following disclaimer.
11   * 2. Redistributions in binary form must reproduce the above copyright
12   *    notice, this list of conditions and the following disclaimer in the
13   *    documentation and/or other materials provided with the distribution.
14   * 3. Neither the name of the copyright holders nor the names of its
15   *    contributors may be used to endorse or promote products derived from
16   *    this software without specific prior written permission.
17   *
18   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
22   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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25   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
28   * THE POSSIBILITY OF SUCH DAMAGE.
29   */
30  package org.objectweb.asm.util;
31  
32  import org.objectweb.asm.AnnotationVisitor;
33  import org.objectweb.asm.Attribute;
34  import org.objectweb.asm.MethodVisitor;
35  import org.objectweb.asm.Label;
36  import org.objectweb.asm.Type;
37  import org.objectweb.asm.signature.SignatureReader;
38  import org.objectweb.asm.util.attrs.Traceable;
39  
40  import java.util.HashMap  ;
41  
42  /**
43   * A {@link MethodVisitor} that prints a disassembled view of the methods it
44   * visits.
45   * 
46   * @author Eric Bruneton
47   */
48  public class TraceMethodVisitor extends TraceAbstractVisitor implements
49          MethodVisitor
50  {
51  
52      /**
53       * The {@link MethodVisitor} to which this visitor delegates calls. May be
54       * <tt>null</tt>.
55       */
56      protected MethodVisitor mv;
57  
58      /**
59       * Tab for bytecode instructions.
60       */
61      protected String   tab2 = "    ";
62  
63      /**
64       * Tab for table and lookup switch instructions.
65       */
66      protected String   tab3 = "      ";
67  
68      /**
69       * Tab for labels.
70       */
71      protected String   ltab = "   ";
72  
73      /**
74       * The label names. This map associate String values to Label keys.
75       */
76      protected final HashMap   labelNames;
77  
78      /**
79       * Constructs a new {@link TraceMethodVisitor}.
80       */
81      public TraceMethodVisitor() {
82          this(null);
83      }
84  
85      /**
86       * Constructs a new {@link TraceMethodVisitor}.
87       * 
88       * @param mv the {@link MethodVisitor} to which this visitor delegates
89       *        calls. May be <tt>null</tt>.
90       */
91      public TraceMethodVisitor(final MethodVisitor mv) {
92          this.labelNames = new HashMap  ();
93          this.mv = mv;
94      }
95  
96      // ------------------------------------------------------------------------
97      // Implementation of the MethodVisitor interface
98      // ------------------------------------------------------------------------
99  
100     public AnnotationVisitor visitAnnotation(
101         final String   desc,
102         final boolean visible)
103     {
104         AnnotationVisitor av = super.visitAnnotation(desc, visible);
105         if (mv != null) {
106             ((TraceAnnotationVisitor) av).av = mv.visitAnnotation(desc, visible);
107         }
108         return av;
109     }
110 
111     public void visitAttribute(final Attribute attr) {
112         buf.setLength(0);
113         buf.append(tab).append("ATTRIBUTE ");
114         appendDescriptor(-1, attr.type);
115 
116         if (attr instanceof Traceable) {
117             ((Traceable) attr).trace(buf, labelNames);
118         } else {
119             buf.append(" : ").append(attr.toString()).append("\n");
120         }
121 
122         text.add(buf.toString());
123         if (mv != null) {
124             mv.visitAttribute(attr);
125         }
126     }
127 
128     public AnnotationVisitor visitAnnotationDefault() {
129         text.add(tab2 + "default=");
130         TraceAnnotationVisitor tav = new TraceAnnotationVisitor();
131         text.add(tav.getText());
132         text.add("\n");
133         if (mv != null) {
134             tav.av = mv.visitAnnotationDefault();
135         }
136         return tav;
137     }
138 
139     public AnnotationVisitor visitParameterAnnotation(
140         final int parameter,
141         final String   desc,
142         final boolean visible)
143     {
144         buf.setLength(0);
145         buf.append(tab2).append('@');
146         appendDescriptor(FIELD_DESCRIPTOR, desc);
147         buf.append('(');
148         text.add(buf.toString());
149         TraceAnnotationVisitor tav = new TraceAnnotationVisitor();
150         text.add(tav.getText());
151         text.add(visible ? ") // parameter " : ") // invisible, parameter ");
152         text.add(new Integer  (parameter));
153         text.add("\n");
154         if (mv != null) {
155             tav.av = mv.visitParameterAnnotation(parameter, desc, visible);
156         }
157         return tav;
158     }
159 
160     public void visitCode() {
161         if (mv != null) {
162             mv.visitCode();
163         }
164     }
165 
166     public void visitInsn(final int opcode) {
167         buf.setLength(0);
168         buf.append(tab2).append(OPCODES[opcode]).append('\n');
169         text.add(buf.toString());
170 
171         if (mv != null) {
172             mv.visitInsn(opcode);
173         }
174     }
175 
176     public void visitIntInsn(final int opcode, final int operand) {
177         buf.setLength(0);
178         buf.append(tab2)
179                 .append(OPCODES[opcode])
180                 .append(' ')
181                 .append(operand)
182                 .append('\n');
183         text.add(buf.toString());
184 
185         if (mv != null) {
186             mv.visitIntInsn(opcode, operand);
187         }
188     }
189 
190     public void visitVarInsn(final int opcode, final int var) {
191         buf.setLength(0);
192         buf.append(tab2)
193                 .append(OPCODES[opcode])
194                 .append(' ')
195                 .append(var)
196                 .append('\n');
197         text.add(buf.toString());
198 
199         if (mv != null) {
200             mv.visitVarInsn(opcode, var);
201         }
202     }
203 
204     public void visitTypeInsn(final int opcode, final String   desc) {
205         buf.setLength(0);
206         buf.append(tab2).append(OPCODES[opcode]).append(' ');
207         if (desc.startsWith("[")) {
208             appendDescriptor(FIELD_DESCRIPTOR, desc);
209         } else {
210             appendDescriptor(INTERNAL_NAME, desc);
211         }
212         buf.append('\n');
213         text.add(buf.toString());
214 
215         if (mv != null) {
216             mv.visitTypeInsn(opcode, desc);
217         }
218     }
219 
220     public void visitFieldInsn(
221         final int opcode,
222         final String   owner,
223         final String   name,
224         final String   desc)
225     {
226         buf.setLength(0);
227         buf.append(tab2).append(OPCODES[opcode]).append(' ');
228         appendDescriptor(INTERNAL_NAME, owner);
229         buf.append('.').append(name).append(" : ");
230         appendDescriptor(FIELD_DESCRIPTOR, desc);
231         buf.append('\n');
232         text.add(buf.toString());
233 
234         if (mv != null) {
235             mv.visitFieldInsn(opcode, owner, name, desc);
236         }
237     }
238 
239     public void visitMethodInsn(
240         final int opcode,
241         final String   owner,
242         final String   name,
243         final String   desc)
244     {
245         buf.setLength(0);
246         buf.append(tab2).append(OPCODES[opcode]).append(' ');
247         appendDescriptor(INTERNAL_NAME, owner);
248         buf.append('.').append(name).append(' ');
249         appendDescriptor(METHOD_DESCRIPTOR, desc);
250         buf.append('\n');
251         text.add(buf.toString());
252 
253         if (mv != null) {
254             mv.visitMethodInsn(opcode, owner, name, desc);
255         }
256     }
257 
258     public void visitJumpInsn(final int opcode, final Label label) {
259         buf.setLength(0);
260         buf.append(tab2).append(OPCODES[opcode]).append(' ');
261         appendLabel(label);
262         buf.append('\n');
263         text.add(buf.toString());
264 
265         if (mv != null) {
266             mv.visitJumpInsn(opcode, label);
267         }
268     }
269 
270     public void visitLabel(final Label label) {
271         buf.setLength(0);
272         buf.append(ltab);
273         appendLabel(label);
274         buf.append('\n');
275         text.add(buf.toString());
276 
277         if (mv != null) {
278             mv.visitLabel(label);
279         }
280     }
281 
282     public void visitLdcInsn(final Object   cst) {
283         buf.setLength(0);
284         buf.append(tab2).append("LDC ");
285         if (cst instanceof String  ) {
286             if (cst == null) {
287                 buf.append("null");
288             } else if (cst instanceof String  ) {
289                 AbstractVisitor.appendString(buf, (String  ) cst);
290             }
291         } else if (cst instanceof Type) {
292             buf.append(((Type) cst).getDescriptor() + ".class");
293         } else {
294             buf.append(cst);
295         }
296         buf.append('\n');
297         text.add(buf.toString());
298 
299         if (mv != null) {
300             mv.visitLdcInsn(cst);
301         }
302     }
303 
304     public void visitIincInsn(final int var, final int increment) {
305         buf.setLength(0);
306         buf.append(tab2)
307                 .append("IINC ")
308                 .append(var)
309                 .append(' ')
310                 .append(increment)
311                 .append('\n');
312         text.add(buf.toString());
313 
314         if (mv != null) {
315             mv.visitIincInsn(var, increment);
316         }
317     }
318 
319     public void visitTableSwitchInsn(
320         final int min,
321         final int max,
322         final Label dflt,
323         final Label labels[])
324     {
325         buf.setLength(0);
326         buf.append(tab2).append("TABLESWITCH\n");
327         for (int i = 0; i < labels.length; ++i) {
328             buf.append(tab3).append(min + i).append(": ");
329             appendLabel(labels[i]);
330             buf.append('\n');
331         }
332         buf.append(tab3).append("default: ");
333         appendLabel(dflt);
334         buf.append('\n');
335         text.add(buf.toString());
336 
337         if (mv != null) {
338             mv.visitTableSwitchInsn(min, max, dflt, labels);
339         }
340     }
341 
342     public void visitLookupSwitchInsn(
343         final Label dflt,
344         final int keys[],
345         final Label labels[])
346     {
347         buf.setLength(0);
348         buf.append(tab2).append("LOOKUPSWITCH\n");
349         for (int i = 0; i < labels.length; ++i) {
350             buf.append(tab3).append(keys[i]).append(": ");
351             appendLabel(labels[i]);
352             buf.append('\n');
353         }
354         buf.append(tab3).append("default: ");
355         appendLabel(dflt);
356         buf.append('\n');
357         text.add(buf.toString());
358 
359         if (mv != null) {
360             mv.visitLookupSwitchInsn(dflt, keys, labels);
361         }
362     }
363 
364     public void visitMultiANewArrayInsn(final String   desc, final int dims) {
365         buf.setLength(0);
366         buf.append(tab2).append("MULTIANEWARRAY ");
367         appendDescriptor(FIELD_DESCRIPTOR, desc);
368         buf.append(' ').append(dims).append('\n');
369         text.add(buf.toString());
370 
371         if (mv != null) {
372             mv.visitMultiANewArrayInsn(desc, dims);
373         }
374     }
375 
376     public void visitTryCatchBlock(
377         final Label start,
378         final Label end,
379         final Label handler,
380         final String   type)
381     {
382         buf.setLength(0);
383         buf.append(tab2).append("TRYCATCHBLOCK ");
384         appendLabel(start);
385         buf.append(' ');
386         appendLabel(end);
387         buf.append(' ');
388         appendLabel(handler);
389         buf.append(' ');
390         appendDescriptor(INTERNAL_NAME, type);
391         buf.append('\n');
392         text.add(buf.toString());
393 
394         if (mv != null) {
395             mv.visitTryCatchBlock(start, end, handler, type);
396         }
397     }
398 
399     public void visitLocalVariable(
400         final String   name,
401         final String   desc,
402         final String   signature,
403         final Label start,
404         final Label end,
405         final int index)
406     {
407         buf.setLength(0);
408         buf.append(tab2).append("LOCALVARIABLE ").append(name).append(' ');
409         appendDescriptor(FIELD_DESCRIPTOR, desc);
410         buf.append(' ');
411         appendLabel(start);
412         buf.append(' ');
413         appendLabel(end);
414         buf.append(' ').append(index).append('\n');
415 
416         if (signature != null) {
417             buf.append(tab2);
418             appendDescriptor(FIELD_SIGNATURE, signature);
419 
420             TraceSignatureVisitor sv = new TraceSignatureVisitor(0);
421             SignatureReader r = new SignatureReader(signature);
422             r.acceptType(sv);
423             buf.append(tab2)
424                     .append("// declaration: ")
425                     .append(sv.getDeclaration())
426                     .append('\n');
427         }
428         text.add(buf.toString());
429 
430         if (mv != null) {
431             mv.visitLocalVariable(name, desc, signature, start, end, index);
432         }
433     }
434 
435     public void visitLineNumber(final int line, final Label start) {
436         buf.setLength(0);
437         buf.append(tab2).append("LINENUMBER ").append(line).append(' ');
438         appendLabel(start);
439         buf.append('\n');
440         text.add(buf.toString());
441 
442         if (mv != null) {
443             mv.visitLineNumber(line, start);
444         }
445     }
446 
447     public void visitMaxs(final int maxStack, final int maxLocals) {
448         buf.setLength(0);
449         buf.append(tab2)
450                 .append("MAXSTACK = ")
451                 .append(maxStack)
452                 .append('\n')
453                 .append(tab2)
454                 .append("MAXLOCALS = ")
455                 .append(maxLocals)
456                 .append('\n');
457         text.add(buf.toString());
458 
459         if (mv != null) {
460             mv.visitMaxs(maxStack, maxLocals);
461         }
462     }
463 
464     public void visitEnd() {
465         super.visitEnd();
466 
467         if (mv != null) {
468             mv.visitEnd();
469         }
470     }
471 
472     // ------------------------------------------------------------------------
473     // Utility methods
474     // ------------------------------------------------------------------------
475 
476     /**
477      * Appends the name of the given label to {@link #buf buf}. Creates a new
478      * label name if the given label does not yet have one.
479      * 
480      * @param l a label.
481      */
482     protected void appendLabel(final Label l) {
483         String   name = (String  ) labelNames.get(l);
484         if (name == null) {
485             name = "L" + labelNames.size();
486             labelNames.put(l, name);
487         }
488         buf.append(name);
489     }
490 }
491
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